VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 401 



formity to nature. But my present endeavour being to rectify the common 

 practice of these medicines by this doctrine, I shall frame, by this method, 

 tables of the purging and vomiting medicines in present use ; better adapted to 

 experience than are hitherto to be found. The method of framing such tables, 

 is by setting off the practicable constitutions in the different ages, that I have 

 observed to take notable quantities of purging and vomiting medicines ; so that 

 by comparing these constitutions with the ages, we have the different doses in 

 all those cases, which is all that is required for a better practice. 



The ages wherein these different doses are taken, I find to be four : when 

 a man is about l6 or 20 years of age, and weighs about 12 stone, he then 

 takes the common dose ; one of Q years of age takes three quarters of that ; 

 one of 6 years the half, and one of 3 years a quarter. Moreover, it having 

 already been shown, that the notable healthy constitutions are but three, as also 

 the notable pulses of each of these ; let then these constitutions be as 2, 3, 4 ; 

 that of the most fluid blood as the first number, and so on ; in that case the 

 dose proper for any person will be found by multiplying the common dose for 

 hris age into the square of his constitution, and dividing by the square of the 

 middle constitution.* For instance, if §j. cassias be the common dose, or the 

 dose of the middle constitution, then 3iij. 9j. and gr. 13^- is the dose of the 

 first constitution ; and 3xiv.gr. 134- that of the grossest or last constitution; 

 and so proportionably for every medicine in all the ages, as appears by the tables. 



This method seems to answer so exactly, that nothing more seems necessary, 

 except a person is more loose or costive than ordinary, which is to be reputed 

 the same as if he had taken an equivalent quantity of a medicine proper to 

 produce these effects. Any physician, who has considered this case in some 

 people after fluxing, will allow the justness of this exception. 



As vomiting medicines have the same common doses with those that purge, 

 they admit also of the like divided doses, which therefore may be found by the 

 same tables. Only, as people that are more costive than ordinary require a pro- 

 portionably greater dose of a purging medicine, so they require their dose of a 

 vomiting medicine to be considerably less, as is very well known in hot coun- 

 tries. It must be observed, that in the tables, age stands instead of quantity 

 of blood, because they increase pretty equally, and it makes the practice more 

 easy to such as are not accustomed to weights and numbers. And the more 

 skilful are to observe, that the mean ages multiplied into the mean constitutions 

 give doses more nicely. 



It has been already observed at p. 250 of this vol. of the Abridgments, that this mode of rea- 

 soning is not applicable to the living body. 



VOL. V. 3 F 



